The present invention provides the compounds with PDE2A selective inhibitories, are used as the drug for preventing or treating schizophrenia, alzheimer's disease etc.. The present invention is compound or its salt representated by formula (I), wherein each symbol is defined as in the description.本發明提供了具有PDE2A選擇性抑制作用的化合物,其用作預防或治療精神分裂症、阿爾茨海默氏疾病等等的藥物。本發明是式(I)所代表的化合物或其鹽,其中每個符號如說明書所定義。